The invention relates to a continuous process for the polymer-analogous reaction of polymers bearing functional groups with reactive compounds.
Continuous processes are widely used in the chemical industry, where they are superior to batch processes due to improved space-time yield, increased flexibility, and with respect to safety considerations, because of the product quality and/or the product mass to be dealt with. A further advantage of continuous processes is that the quality of the resultant product can be controlled by on-line analysis during the running production process, by changing reaction parameters such as flow rate, temperature, etc.
The continuous processes which have been described hitherto in the chemical industry involve the reaction of monomeric compounds to give novel but likewise monomeric compounds, or involve the preparation of polymers from monomers and/or oligomers, e.g. by polycondensation or polymerization.
Examples of the first process from silane chemistry are the continuous gas-phase hydrosilylation of silanes by compounds bearing organic double bonds or triple bonds, e.g. hydrosilylation of a trichlorosilane by acetylene, disclosed by M. Bogdan et al., Appl. Organomet. Chem. 1 (3), 1987 pp. 267 to 73. In these processes, the starting materials are always, gaseous or low-viscosity compounds under reaction conditions. In general, the products have similar properties as well. In the case of volatile starting materials (b.p.  less than 200xc2x0 C. at 1 mbar pressure), a portion of starting material which is not completely reacted when so-called loop reactors are used must be recirculated to the reaction circuit. This leads, for example, to a low space-time yield, to a longer mean residence time, and to a longer thermal stress on the product.
For polymer preparation, there are likewise a number of different continuous processes. Thus, for example, EP-A-382 366 describes the hydrolysis and condensation of dimethylchlorosilanes to give oligomeric siloxanes in continuous operation.
Continuous processes for xe2x80x9cpolymer-analogous reactionsxe2x80x9d are not known, polymer-analogous reactions being defined as chemical reactions on macromolecules which do not cause changes in their backbone and leave their degree of polymerization unchanged. An example of such a reaction is the saponification of poly(vinyl acetate).
The object of the present invention was to develop a continuous process by which reactive groups on polymers can be continuously reacted in a polymer-analogous manner with monomeric, oligomeric or polymeric reactants.